#include <iostream>
using namespace std;

class A {
public:
	A(void) {
		cout << "A::A(void)" << endl;
		num = 0;
	}
	int num;
};

class B {
public:
	/*B (void) {}*/
	int num2;
	A m_a;
};

int main (void)
{
	B b;
	cout << b.num2 << endl;//未初始化的结果
	cout << b.m_a.num << endl;//0
	return 0;
}
